fiberglass plastic toroid

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: dest <dest@xxxxxxxxxxx>

Hallo : )

                            preface.

      "From: Terry Fritz <twftesla@xxxxxxxxxx>
      Date: Sun, 25 Jul 1999 19:25:09 -0600

      My new aluminum duct torroid came back today with the usual
      little dings and dents.  They seem to last about three sessions
      (with car travel) before they need replacement.  Not a big deal
      but a super resilient torroid would really be nice..."


i don`t understand how people can use "bare" ducting at all - it`s so
unstable in form and easy to dent or bend : ) probably most people
usually construct something very tiny (like 4" by 18" for example),
and at this size ducting strength is yet adequate, but when i was
trying to make 10" by 40" i quickly discovered, that its mechanical
properties are just crap. maybe it was just a bad luck, or just my
"armchair coiler" hands growing from wrong place, i don`t know : )
later i tried to wrap a whole thing with clear scotch tape and
it helped alot - at least the thing stop bending from its own
(1.5kg at that time) weight : D it`s even start looking more or less
smooth:

http://himplast.ru/dest/tesla/toroid/tor30.JPG
http://himplast.ru/dest/tesla/toroid/tor32.JPG

but i still was able to do noticeable damage just by pressing on the
surface with my bare finger. after some time i have read on the list
post from Dr. R., where he quoted prices on spun aluminium toroids of
various sizes and i laughed very hard about those things -
"30 inch dia. --- $975.00", and this was bulk order! : D
then i`ve read that aluminium toroids are rather heavy, and more
important (as Steve Conner said) - "Some spun toroids dent very
easily" - heck, and i must pay for thit crap > 500$? NO WAY! : )))

so i decided to do all by myself - i wanted a cheap ducting toroid of
10" by 40" that i can kick, throw in the car or store just on the
floor without any dents. i was looking on the Gary Lau`s foam toroid
in the past, but i don`t like it - mechanical properties of just pure
resin coating are poor - it will just crack and shatter if you kick it
hard. so i decided to go by fiberglass plastic route.

it`s very important to note the following:

1. i am "armchair coiler" and this was my very first attempt to do
_anything_ by hands - absoltely NO any experience or even some basic
skills - you can do MUCH better : )))
2. i know nothing about epoxy/fiberglass or such things - only some
very basic knowledge - the guys who knows some tricks & tips my do
MUCH better again ; )
3. i was not attempting to do it as smooth as spun one - just robust,
tho after finishing i realized that it would be very easy to
accomplish.

and here are the results of my very crude attempts % )

http://himplast.ru/dest/tesla/toroid/tor01.JPG
http://himplast.ru/dest/tesla/toroid/tor02.JPG
http://himplast.ru/dest/tesla/toroid/tor06.JPG
http://himplast.ru/dest/tesla/toroid/tor07.JPG
http://himplast.ru/dest/tesla/toroid/tor08.JPG

note that i have not even try to grind joints yet, not to mention
polishing the whole surface. how it looks on the top of the "coil":

http://himplast.ru/dest/tesla/toroid/tor13.JPG
http://himplast.ru/dest/tesla/toroid/tor22.JPG
http://himplast.ru/dest/tesla/toroid/tor23.JPG
http://himplast.ru/dest/tesla/toroid/tor24.JPG
http://himplast.ru/dest/tesla/toroid/tor25.JPG
http://himplast.ru/dest/tesla/toroid/tor26.JPG

here are some results of the first unsuccessful attempts in finding
right proportion of resin:catalyst:accelerator, right time for soaking
glass fibre mat in resin and trying to cover the ducting evenly:

http://himplast.ru/dest/tesla/toroid/tor03.jpg
http://himplast.ru/dest/tesla/toroid/tor04.jpg
http://himplast.ru/dest/tesla/toroid/tor05.jpg

but there were only 3 errors, so i ruined only 2 piece of mat (from
total of 32) and 225 ml of resin (from total of 3600 ml) so it`s ok.

now the most fun part - dest_ructive testing : )))

1. http://himplast.ru/dest/tesla/toroid/kickin.avi

i`m laying some thick linoleum on the floor, laying toroid on it and
trying to kick it with my feet : ))) there is only 10 fps, so video
is not showing real dynamics of the kicks - they are looking a bit
"slow" and "soft" - that`s not 100% correct. and btw - this thing
weigh 4.5 kg - just try to kick such mass on soft thick linoleum.

2. http://himplast.ru/dest/tesla/toroid/knockin.avi

i`m taking a hard wooden block with srarp edges and trying to make
some dents by knocking on the surface - listen to the sound of this
knocks : ))) unfortunatelly i failed to demonstrate the sharpness of
the edges - stupid camera fixed it`s focus right after pressing
"record" button.

3. http://himplast.ru/dest/tesla/toroid/squizin.avi

here i`m putting small sheet of thick (1 cm) acrylic right on the
toroid and then put a 30 kg variac on this sheet! it`s somewhat hard
to see the weight of the variac in video, so i took one still for ya:

http://himplast.ru/dest/tesla/toroid/tor27.JPG

you may hear some cracking in the backgroung - don`t worry - that`s
not my toroid : ))) it`s just a debris on the floor - you can check it
when i walk away/to the toroid - the same sound.
why i put those 30 kg so slow? coz i placed acrylic a little askew -
you can see how the variac trying to fall towards the camera : )

conclusion - even the most lame "coiler" can make very light (4.5 kg),
very strong (your kids can take it to fool around with it on the
river : D), very cheap for its size (total cost was about 120$ - here,
in russia, where ALL components that i used was imported)
10" by 40" toroid. and i think that even John Freau would never be
able to do something as big and ugly as i did : )))

-----
Let the bass kick! =:-D